Allium 'Globemaster'
Allium 'Globemaster' · Amaryllidaceae Popular
Enormous, dense, violet-purple globes up to 25 cm across on sturdy stems. It is sterile, so the flowers last for a month, twice as long as other alliums.
- Size
- 3 ft tall, 12 in wide
- Zones
- 5 to 8
- Light
- Full sun
- Flowers
- Late May to late June
- Pets
- Toxic (moderate)
- Job in a bed
- Accent
A bed built around allium 'Globemaster'
The planner designed this bed around allium 'Globemaster' when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun. It chose the other plants from the 715 that suit those conditions and its dry soil, and says below why allium 'Globemaster' stands where it does.
The plants
- 1 Common thyme × 9, lavender
- 2 Sedum 'Lidakense' × 27, pink
- 3 Wild quinine × 3, white
- 4 Brown-eyed Susan × 3, yellow
- 5 Dwarf English boxwood × 1, dark green leaves
- 6 Betony 'Hummelo' × 3, purple
- 7 Allium 'Globemaster' × 3, purple
- 8 Spring starflower × 7, blue
Why this plant
- The only globes. The others are dense clusters, flat plates, daisies and others. Shape reads at a distance, where colours blur.
Why here
- Forward of its height. At 3 ft it is taller than betony 'Hummelo' (20 in) behind it, but airy enough to see through.
- 3 plants in 3 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
Why now
- In flower for five weeks. From late May to late June.
- Part of the bed's peak. With common thyme and wild quinine in late June: 3 kinds at once. No week has more.
- Leaves gone by midsummer. They die back and leave bare ground. A perennial that comes up late stands beside it, and grows over the gap.
Planned as an English border: 5 of the 6 groups (83%) are drifts, longer along the bed than they are deep. The most in flower at one time is 3 kinds, from late June. Cool colours (lavender, pink, purple and blue) with yellow as the warm note, and white to calm things between them.
The planner's own design check: 12 Excellent, 5 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where allium 'Globemaster' goes in a border
At 3 ft it belongs in the middle of a bed. In the planner's ten height classes it is medium tall (2½ to 3 ft). It is airy enough to see through, so it can also come forward and veil what is behind it.
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
The best big allium: the flowers last longest and the stems never need support. Repeat it along a border to carry the eye, between the tulips and the first summer flowers.
- The largest allium flowers
- A long display in late spring
- Bridging spring bulbs and summer perennials
What to plant with allium 'Globemaster'
Plants recorded as good partners for it, and what each pairing does:
- Catmint 'Walker's Low': in flower together for five weeks, from late May; grows up in time to hide its dying leaves; fine leaves against its bold ones.
- Peony: in flower together for four weeks, from late May; grows up in time to hide its dying leaves; medium leaves against its bold ones.
- Salvia 'May Night': in flower together for four weeks, from late May; grows up in time to hide its dying leaves; medium leaves against its bold ones.
Choosing between it and a look-alike? Allium 'Globemaster' vs Ornamental onion 'Purple Sensation'.
Questions about allium 'Globemaster'
Does allium 'Globemaster' need sun or shade?
Allium 'Globemaster' grows in full sun (6 or more hours of direct sun a day).
It wants dry, sharply drained soil, of average fertility, and little watering once settled.
What zones does allium 'Globemaster' grow in?
USDA zones 5 to 8. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does allium 'Globemaster' flower in my zone?
In zone 5 it flowers late May to late June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 5 | Late May to late June |
|---|---|
| Zone 6 | Mid May to late June |
| Zone 7 | Early May to mid June |
| Zone 8 | Early May to mid June |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should allium 'Globemaster' be planted?
10 in (25 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 12 in (30 cm), so a group knits into one patch.
It grows 3 ft (90 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many allium 'Globemaster' plants do I need?
At 10 in apart, set out in staggered rows:
- 17 to fill 10 square feet (about 1 m²)
- 13 for a single row 10 ft (3 m) long
- 55 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used three in three groups.
Is allium 'Globemaster' poisonous to dogs and cats?
Yes: moderate toxicity to people, dogs, cats and horses. Like all onions, it can damage red blood cells in dogs, cats and horses if eaten. Eating the bulbs in quantity can also upset a person's stomach.
Rated from the ASPCA. Where references disagree, the more cautious rating is used.
What can I plant to hide allium 'Globemaster''s leaves after it flowers?
A bulb's leaves have to be left to yellow for about six weeks after flowering, to feed next year's flowers. Plant it among perennials that come up late and spread wide, and they grow over the leaves as they fade:
- Peony: 3 ft tall and 3 ft wide, a recorded partner, in flower late May to late June.
- Catmint 'Walker's Low': 24 in tall and 2½ ft wide, a recorded partner, in flower mid May to mid September.
- Daylily: 2½ ft tall and 24 in wide, in flower late June to early August.
What does allium 'Globemaster' look like in winter?
Allium 'Globemaster' is underground: it dies back after flowering and waits as a bulb until spring. Mark where it is, so a fork does not find it first.
More Allium
- Allium 'Ambassador' Allium 'Ambassador'
- Allium 'Gladiator' Allium 'Gladiator'
- Allium 'Mount Everest' Allium 'Mount Everest'
- Blue allium Allium caeruleum
- Chives Allium schoenoprasum
- Curly onion Allium senescens subsp. glaucum
- Drumstick allium Allium sphaerocephalon
- Garlic chives Allium tuberosum
- Giant allium Allium giganteum
- Golden garlic Allium moly
- Japanese onion 'Ozawa' Allium thunbergii 'Ozawa'
- Nodding onion Allium cernuum
- Ornamental onion 'Millenium' Allium 'Millenium'
- Ornamental onion 'Purple Sensation' Allium hollandicum 'Purple Sensation'
- Ornamental onion 'Summer Beauty' Allium 'Summer Beauty'
- Pink lily leek Allium oreophilum
- Schubert's allium Allium schubertii
- Sicilian honey garlic Allium siculum
- Star of Persia Allium christophii
- Turkestan onion Allium karataviense
In these guides
Every fact on record
- Type
- Bulb
- Size
- 3 ft (90 cm) tall, 12 in (30 cm) wide
- Plant
- 10 in (25 cm) apart
- Height class
- Medium tall (2½ to 3 ft)
- Place in the bed
- Middle, or further forward: it is airy enough to see through
- Flowers
- Late May to late June; globes; purple
- Leaves
- Bold texture, summer-dormant; green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 5 to 8
- Light
- Full sun
- Soil
- Average, dry and sharply drained
- Water
- Low
- Feeding
- None needed
- Family
- Amaryllidaceae
Checked against ASPCA poison lists. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.